• The Journal of the Acoustical Society of Korea
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• v.39 no.2
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• pp.120-130
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• 2020

This paper solves the problem in underdetermined convolutive mixture by improving the disadvantages of the multichannel nonnegative matrix factorization technique widely used in blind source separation. In conventional researches based on Spatial Covariance Matrix (SCM), each element composed of values such as power gain of single channel and correlation tends to degrade the quality of the separated sources due to high variance. In this paper, level and frequency normalization is performed to effectively cluster the estimated sources. Therefore, we propose a novel SCM and an effective distance function for cluster pairs. In this paper, the proposed SCM is used for the initialization of the spatial model and used for hierarchical agglomerative clustering in the bottom-up approach. The proposed algorithm was experimented using the 'Signal Separation Evaluation Campaign 2008 development dataset'. As a result, the improvement in most of the performance indicators was confirmed by utilizing the 'Blind Source Separation Eval toolbox', an objective source separation quality verification tool, and especially the performance superiority of the typical SDR of 1 dB to 3.5 dB was verified.

• Journal of The Korean Association For Science Education
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• v.24 no.6
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• pp.1082-1093
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• 2004

The purpose of the study was to compare science curriculum documents of the several countries including Korea, the United States, the United Kingdom, Japan, and Singapore. The comparison focused on goals and contents in science education of each country. The goals for science education in each country were very similar. They included understanding knowledge, acquiring inquiry skills, developing positive attitudes towards science, and appreciating S-T-S in most countries. But each country's goal setting level was different; some countries set the same goals for several grades and other countries set different goals for each grade. Goals provided for each grade were more specific and elaborated. Science contents were categorized differently in each country. In Korea, science contents were categorized in energy, matter, living things, and earth. On the other hand, science contents were composed of 8 categories including unifying concepts and processes in science, science as inquiry, physical science, life science, earth and space science, science and technology, science in personal and social perspectives, and history and nature of science in the United States. In the United Kingdom, science enquiry, life processes and living things, materials and their properties, and physical process were categories for science contents. In Singapore, science contents were organized by themes relevant to students' everyday experience. Implications for goals and contents in science education to prepare students to live and work in a future society were suggested based on the results of the study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.712-719
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• 2014

This study was carried out to evaluate the effects of trehalose on quality characteristics of white pan bread. Basic formula consisted of bread flour, 6% sucrose, and 0, 2, 4, 6% trehalose, respectively. Loaf volume, specific loaf volume, baking loss rate, moisture content, water activity, crumb color, and sensory evaluation scores were determined for quality characteristics of bread. White pan bread containing 4% trehalose had a higher loaf volume of 2,140 mL and specific loaf volume of 3.96 mL/g. Baking loss rate of white pan bread was the lowest in the loaf containing 6% trehalose. In crumb texture analysis, hardness of loaf containing 4% of trehalose was the lowest after 7 days of storage. Moisture content and water activity of white pan breads increased with increasing level of trehalose. Color of crumbs was the brightest in the loaf containing 6% trehalose. White pan bread containing 4% trehalose scored better in the sensory evaluation than the others. As a result, trehalose affected quality characteristics of white pan bread. Especially, the addition of 4% trehalose to white pan bread had beneficial effects on quality characteristics.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.2
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• pp.117-123
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• 2012

In order to dispose of the LILW(low and intermediate level radioactive waste) stored at KAERI, the radwaste drum assay system will be introduced to evaluate the radioisotopes inventory of stored drums. At present, the construction project of the dedicated assay facility to operate it and carry out routine maintenance of that equipment has been conducting at the radwaste treatment facility. Since that facility will be constructed in front of a 1st radwaste storage facility as well as the radwaste drums to be assayed and the transmission source in the radwaste drum assay system are in that facility, they could act as the radioactive sources and then, would affect the dose rate at the inside and the outside of the facility. Therefore, the radiation shielding should be evaluated through the concrete wall near to the radioactive sources whether the wall thickness is sufficient against the regulations. In this study, the radiation safety for the concrete wall around the radiation controlled area in the radwaste drum assay facility was evaluated by the MCNP code. From the evaluation results, the thickness of those concrete walls which are under consideration of about 30 cm was enough to shield the radiation from the radioactive sources.

• Korean Journal of Health Education and Promotion
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• v.23 no.4
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• pp.173-192
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• 2006

Objectives: This job analysis of a staff in charge of quit-smoking policy at public health centers aims at providing fundamental information to establish strategies supporting various quit-smoking. Methods: The job analysis of a staff in charge of quit-smoking policy at public health centers was carried out through DACUM(Development of Curriculum) method from April through May 2006. Three experts had developed job description with staffs in charge of quit-smoking policy at public health centers through two workshops. The survey was practiced for staff in charge of quit-smoking policy at the other public health centers. The characteristics of the staffs such as age, years for working at public health center, years for charging with quit-smoking work, the proportion of responsibility for quit-smoking work, were surveyed. Results: The research has reached the conclusions below. 1. The job description have been developed considering input-process-outcome axis and plan-do-evaluation axis for quit-smoking policy at public health centers. The final job description is composed of 3 missions, 7 accountabilities, 20 sub-work items. 2. The quit-smoking activity mostly focused at direct education and counselling. But planing and evaluation activity for quit-smoking have been under-achieved. 3. The staffs for quit-smoking policy were feel it is easy to educate and counsel to comer to public health centers for quit-smoking. But having the high proportion of responsibility for quit-smoking policy have usually difficult to do that. So they want to education about counselling for smoker. 4. The staffs who worked over the 2 years for quit-smoking policy the public health center have responded that investigate the smoking rate of the jurisdiction community and the problem of the culture about smoking and smoking policy is important. Conclusions: The study helps reinforcing the initiatives of central government for quit-smoking policy at public health centers. Especially staffs want education in technology area for counselling smoker. And they want nationwide supporting for investigating smoking rate and related factors at the local level.

• Earthquakes and Structures
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• v.13 no.1
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• pp.59-66
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• 2017

Modern seismic codes rely on performance-based seismic design methodology which requires that the structures withstand inelastic deformation. Many studies have focused on the inelastic deformation ratio evaluation (ratio between the inelastic and elastic maximum lateral displacement demands) for various inelastic spectra. This paper investigates the inelastic response spectra through the ductility demand ${\mu}$, the yield strength reduction factor $R_y$, and the inelastic deformation ratio. They depend on the vibration period T, the post-to-preyield stiffness ratio ${\alpha}$, the peak ground acceleration (PGA), and the normalized yield strength coefficient ${\eta}$ (ratio of yield strength coefficient divided by the PGA). A new inelastic deformation ratio $C_{\eta}$ is defined; it is related to the capacity curve (pushover curve) through the coefficient (${\eta}$) and the ratio (${\alpha}$) that are used as control parameters. A set of 140 real ground motions is selected. The structures are bilinear inelastic single degree of freedom systems (SDOF). The sensitivity of the resulting inelastic deformation ratio mean values is discussed for different levels of normalized yield strength coefficient. The influence of vibration period T, post-to-preyield stiffness ratio ${\alpha}$, normalized yield strength coefficient ${\eta}$, earthquake magnitude, ruptures distance (i.e., to fault rupture) and site conditions is also investigated. A regression analysis leads to simplified expressions of this inelastic deformation ratio. These simplified equations estimate the inelastic deformation ratio for structures, which is a key parameter for design or evaluation. The results show that, for a given level of normalized yield strength coefficient, these inelastic displacement ratios become non sensitive to none of the rupture distance, the earthquake magnitude or the site class. Furthermore, they show that the post-to-preyield stiffness has a negligible effect on the inelastic deformation ratio if the normalized yield strength coefficient is greater than unity.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.507-514
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• 2010

This study was performed to reduce unpleasant taste and flavor of $Gastrodia$ $elata$ Blume as well as to improve utilization as functional food materials using fermentation. The component, antioxidant activity, and taste test were compared between fresh and fermented $Gastrodia$ $elata$ Blume powder (FGP). FGP contained higher level of total fat, protein, mineral, and fiber than raw material. The pH of FGP was higher compared to raw $Gastrodia$ $elata$ Blume powder (RGP), and antioxidant activity was as high as vitamin C regardless material status (raw vs. fermented). This result indicated that its activity was not decreased by fermentation. Dispersiveness and solubility of $Gastrodia$ $elata$ Blume powder was the best in 60-70 mesh. For sensory evaluation, FGP or RGP was mixed with either orange juice or yoghurt. The results showed that overall preference, taste, flavor, texture, and color were better in fermented $Gastrodia$ $elata$ Blume drinks than in raw ones. It is plausible that unpleasant taste and flavor of $Gastrodia$ $elata$ Blume was declined by fermentation. Thus, fermentation can be easily applied to eliminate unpleasant smell in $Gastrodia$ $elata$ Blume, and FGP can be mixed with other beverages to produce healthy food and drinks.

• Journal of Korea Water Resources Association
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• v.54 no.9
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• pp.667-680
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• 2021

We investigated changes in frost days and frost-free periods and to comparatively assess frost event prediction models developed using logistic regression (LR), random forest (RF), and long short-term memory (LSTM) networks. The meteorological variables for the model development were collected from the Suwon, Cheongju, and Gwangju stations for the period of 1973-2019 for spring (March - May) and fall (September - November). The developed models were then evaluated by Precision, Recall, and f-1 score and graphical evaluation methods such as AUC and reliability diagram. The results showed that significant decreases (significance level of 0.01) in the frequencies of frost days were at the three stations in both spring and fall. Overall, the evaluation metrics showed that the performance of RF was highest, while that of LSTM was lowest. Despite higher AUC values (above 0.9) were found at the three stations, reliability diagrams showed inconsistent reliability. A further study is suggested on the improvement of the predictability of both frost events and the first and last frost days by the frost event prediction models and reliability of the models. It would be beneficial to replicate this study at more stations in other regions.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.9
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• pp.1-16
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• 2019

This study was carried out to develop a physics education program for foreign students of university in Korea to improve their ability to major in the field and to prevent them from becoming dropout. The subjects of the study are five Chinese students attending a natural science and engineering college. Prior to the development of the physics education program, the researchers developed basic physics textbooks for the foreign students and questionaries for diagnosis and summative evaluation, and utilized them to apply a total of seven classes. After the application of the classes, the results of the student's diagnosis and summative evaluation, the teacher's diaries, the observer's diaries, and the transcripts were analyzed by triangulation method. In addition, Nvivo12 was used for the analysis of the teacher's and observer's diaries to help with qualitative analysis. The results of the study are as follows: First, the oder and contents of physics education program for students of the natural science and engineering college were presented in detail, and basic physics textbooks and tools for diagnosis and summative assessment were developed. Second, as a result of the analysis of the diagnosis and summative assessment results of the program, the students' basic physics achievement improved by an average of 40 points due to the application of the developed program. Third, as a result of the application of the program using Nvivo12, meaningful node and actual cases were extracted. There were 10 types of nodes created such as understanding of the students, teaching method, rate of the participation, level differences, language problems, relevance to majors, curriculum and methods of education in the country of origin, cooperative learning, and interest inducement. The researcher provided suggestions on physics education methods for students of science and engineering colleges in Korea based on the related cases.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.559-565
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• 2022

In this study, we intend to develop a granulation tissue formation model. As a pilot experiment, a contrast agent was injected into the pylorus in 3 rats, the normal pylorus lumen size was confirmed, and a stent was placed. Stent migration was confirmed in to the duodenum within 1 week. In this experiment, stent was sutured and fixed to induce granulation tissue formation after gastrostomy under a fluoroscopic guidance. Twenty rats were divided into Healthy Group / Gastrostomy Group. After anesthesia of the Gastrostomy Group, an abdominal incision was performed, and gastrostomy was performed under a fluoroscopic guidance, and a stent was placed into the pylorus. In order to prevent stent migration due to peristalsis, suture between the pylorus and the proximal end of the stent was performed. Postoperative behavior and weight changes were monitored daily. Four weeks after surgery, gastrointestinal fluoroscopy imaging was performed and rats were sacrifices. To evaluate the degree of granulation formation, the stent was sectioned transversely. Gastrostomy group was statistically significantly higher than Healthy Group in granulation area ratio (all p<.001). In conclusion, it is considered that the level of tissue overgrowth formation for preclinical evaluation of the pylorus stricture model through gastrostomy is appropriate as a research evaluation tool.